Wireless communication network includes multiple base stations, each with a coverage area and serve multiple user equipments (UEs) within the coverage area. The UEs associates with the base stations and the communications between base stations and the UEs provide access capability to the UEs, and may be asymmetric, i.e., having different downlink and uplink data rates respectively.
In order to support higher data rates, wideband code division multiple access (WCDMA) network introduced high speed downlink packet access (HSDPA) and high speed uplink packet access (HSUPA) features. The HSDPA improves the downlink data transmission, whereas the HSUPA improves the uplink data transmission. In order to reduce the transmission delays, packet scheduling functionality is moved from a radio network controller (RNC) to the base stations called as MAC-hs in downlink side and MAC-e in uplink side. Further, the HSDPA introduces a downlink common channel (HS-DSCH) shared to all UEs (alternatively referred as users) whereas the HSUPA uses an enhanced dedicated channels (E-DCH) for each UE. In downlink, packet scheduling is performed through a round robin method based on parameters such as channel quality or the like. In the uplink, several scheduling mechanisms can be possible as the UEs can transmit in parallel with a low bit rate or the round robin method where few UEs can transmit with high rate based on priority, service type or channel quality and so on.
In a conventional method, the scheduling is performed in such a way that all the UEs can transmit in parallel with a low bit rate. The performance of this method depends on the receiver decoding capacity. The receiver capacity is calculated on the basis of maximum allowable 1% bit error rate (BER) (or 10% BLER), which defines the spreading factor with respect to number of users. As the number of users increases, the possible spreading factor (SF) also increases in order to reduce the inter-user interference. When a single user is in the system the higher grant is given to the user for better transport block and the maximum possible SF will be 2×SF2 for Category 4. Other possible transport blocks have 2×SF4 for category 4, SF4, SF8, SF16, SF32 and SF256 for category 1. For example, if a second user is added, both can go up to SF4 of category 1. This is closer to the single user capacity for category 2 2×SF4 configuration. So approximately 1.4 kbps cell throughput is possible. Similarly, every addition of user will further increase SF and reduces the user throughput in such a way that approximately cell throughput of 1.4 kbps can be maintained.
In another conventional method, few users can transmit with high bit-rate with Round Robin fashion which gives better cell throughput. Here, the inter-user interference is avoided drastically. In this method the average cell throughput is almost close to the cell throughput of single user case. In this case, if the user got scheduling but does not have activity, in such a case the overall cell throughput drops as user is not fully utilizing. In other certain conditions where different users experiencing different channel conditions the cell throughput can be further improved by prioritizing the user with best channel conditions. But this might cause the other users to stop getting resources as per their service type. This method does not work efficient in certain scenarios as user gets grant over scheduled period of interval which leads to delays in response which intern drops the cell throughput in both uplink and downlink side.
The above information is presented as background information only to help the reader to understand the present invention. Applicants have made no determination and make no assertion as to whether any of the above might be applicable as Prior Art with regard to the present application.